Current local area or zone dimming direct LED backlight systems contain from dozens to hundreds of individual LEDs, supporting circuitry and other components.
Some LED direct back light panels have each LED or groups of LEDs controlled where black areas of a scene do not have light attempting to pass through the LCD display. Controlling single or groups of LEDs is referred to as local dimming or zone dimming.
Direct LED backlight systems are relatively thick in profile and generally have a diffuser sheet sitting in front of the backlighting panel to soften and mix the light from the panel to eliminate any banding of the emitted light. The assembly may further have another sheet or film with micro prisms and/or micro lens to help steer the light directly to the LCD panel which improves the efficiency of the emitted light from the backlight panel. Between the individual panels, sheets and films, there are often air gaps to allow the light to mix into more of a homogenous beam before entering the next sheet or film.